"w_tom" wrote in message

What is this sag that causes problems? Computer power
supplies are some of the most robust electronics in the
house. AC electric can drop to 90 VAC (for 120 VAC) or 190
VAC (for 230). The computer must operate interrupted. Even
with a full load of peripherals, the computer must power up
just fine when AC mains voltage has sagged that low.

Incandescent bulbs would be at less than 40% intensity and
the computer must work just fine. However many buy power
supplies only on on specification - price - and get what they
paid for. Sags must not damage any computer. However if you
are still using disk filesystems such as FAT, then you still
data destruction from excessive brownouts or blackouts can
occur. Again, the UPS is nice, but not necessary for hardware
protection if computer hardware is properly selected and
installed.

I never use plug-in UPSes or any other grossly overhyped and
ineffective plug-in protectors. I go online during every
thunderstorm. Never shutdown for such storms. Never unplug
anything. Suffered some direct strikes and never suffered
damage. No damage because the technique is same well proven
methods demonstrated in 1930s research papers.

Those plug-in protectors fundamentally violate those
principles. Summary is provided in "Opinions on Surge
Protectors?" on 7 Jul 2003 in the newsgroup
alt.certification.a-plus or
http://tinyurl.com/l3m9

BTW, plug-in surge protector and plug-in UPS use equivalent
circuits to provide the same ineffective protection. There is
no such thing as blocking or stopping a surge even with a
transformer. Transformer can help to divert the surge. But
again, it still requires the well proven 'whole house'
protection 'system'. Yes - a 'system' that includes the most
critical 'system' component - earth ground.

Plug-in UPS serves one primary function - data protection.
Surge protector is defined by its most critical component -
that plug-in protectors just don't have and forget to
mention. Read that above, previous summary discussion for
details.


Vanguard wrote:
"Ben" wrote in message
If I get one of these UPS surge protectors would that mean I
could use my computer during a thunder storm?
thanks,
Ben

Better to install a whole-home surge protector rather than the
cheapie surge protectors you buy at the store. They cost about
the same (unless you need to have an electrician do the wiring for
the home surge arrestor). Then everything in your house is
protected. however, surge arrestors only protect against surges.
They don't protect against sags. Your power supply would have to
suck more current to offset the loss in voltage until the sag
became too low (your lights and television will work but not the
switching power supply in your PC). Surge protectors also do
little to condition the line (but then some cheapie UPSes are
just pass-through units, too). I prefer to get a UPS that
generates the power output rather than just pass it through. A
UPS with an isolating transformer is even better but then they get
really heavy; mine weighs 60 pounds for the case with transformer
and another 60 pounds for the 2 batteries, for too many other
goodies to list, but then it cost as much as a high end PC). But
even a cheapie UPS is usually better than a surge protector. You
could spend $60 on a good point-of-use surge protector (i.e., you
plug it in the wall install of the point-of-entry whole-home surge
arrestor) and hope that it is still working (since many never tell
you when they've gotten fried) or you spend twice that much on a
low-end UPS that protects better. When the power goes out, the
surge protector doesn't do anything. It can be handy to continue
computing while the power is out. You're television don't work so
sit at your PC. You can check the weather, especially if that
caused the outage. You can contact your power company (since
calling in puts in the queue with everyone else trying to report
the outage). You can even hook up a low-power intensity lamp so
you can see without having to drain the batteries in your
flashlights. I actually have a small UPS left over from a prior
system used to power the cable modem and a flourscent lamp,
and it's small enough to tote around the house to use elsewhere.
Sure beats sitting in a dark house.

If the voltage drops on the input side but you still have the same power
demands on the output side and where you must maintain the same voltage
requirements with the same demand for current, how does the power supply
make up for the deficiency in input voltage?

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